The invention relates to a metal laminate gasket with partial bead sections to securely seal around cylinder bores.
An internal combustion engine has been developed to provide high power and light weight. For this purpose, a cylinder head is made of light metal, such as aluminum alloy, and the distance between cylinder bores is reduced as little as possible. In this kind of an engine, since the rigidity of the cylinder head is not so strong, when the cylinder head is fixed to a cylinder block, a middle portion of the cylinder head is liable to project upwardly.
On the other hand, a cylinder head gasket installed between the cylinder head and the cylinder block has been made to satisfy the requirement of the engine. Since a metal laminate gasket is strong against high temperature and has a durability, the metal laminate gasket has been used widely.
In order to form a light weight metal laminate gasket, it is preferable to reduce a number of metal plates laminated together. Therefore, a metal gasket formed of two metal plates has been used. In the gasket formed of two metal plates, however, it is difficult to securely seal around the cylinder bores especially when the cylinder head deforms due to the insufficient rigidity as explained above.
In order to form a strong and wide sealing area around a hole to be sealed, U.S. Pat. No. 4,896,891 and U.S. Pat. No. 4,938,488 have been proposed. Although these patents provide strong and wide sealing areas, in case the rigidity of the cylinder head and the cylinder block is not strong, these gaskets are not proper.
In view of the foregoing, the present invention has been made, and an object of the invention is to provide a metal laminate gasket, which can prevent reduction of a surface pressure at a sealing portion even if the rigidity of the cylinder head is not strong.
Another object of the invention is to provide a metal laminate gasket as stated above, wherein the surface pressure to be formed around a hole can be adjusted easily.
A further object of the invention is to provide a metal laminate gasket as stated above, wherein the surface pressures around the cylinder bores can be adjusted easily with reference to the overall distribution thereof.
Further objects and advantages of the invention will be apparent from the following description of the invention.